Bonding pin



' May 3.1927.

, 1,626,909 L- H. AYER BONDING PIN I Filed Feb. 9, 1923 loads By? 67 Patented May 3, 1927.

Ut ii t lill) STATES LOUIS H. AYER, OF CHICAGO, ILLINOIS.

BONDING PIN.

Application filed February 9, 1923.

My invention relates to bonding pins of the type which are used for connecting electrical conductors to rails.

Tapered bonding pins are commonly employed for connecting electrical conductors to rails, such pins being formed with one or more longitudinal grooves in which the conductoris clamped by wedging engagement of the pin in an aperture of the rail. It is customary to make these tapered pins of circular cross section so that .a substantially uniform compressing strain is imposed on the pin as it is driven into the aperture of the rail, and the depth and arrangement of the groove is such that a substantial portion of the conductor is exposed for direct wedging engagement with the aperture of the rail. This construction however, results in a considerable mutilation or peeling back of the conductor which of comparatively soft material at the edge or corner of the aperture, and not only reduces the conducting capacity but also increases the liability of breakage.

The principal objects of my invention are to minimize the peeling back or mutilation of the side of the conductor when clamped to a rail by means of a bonding pin; to construct the bonding pin so that the compress ing strain resulting from the wedging engagement of the pin in the aperture of the rail tends to compress or force and close the sides of the bonding pin over the exposed portion of the conductor to frictionally e11 gage the wire or conductor on all sides or entirely around its circumference to prevent peeling or shearing; to effect a better electrical connection as well as a more substantial mechanical connection; and in general, to provide an improved bonding pin which is simple and inexpensive and capable of being used in place of other bonding pins with out requiring any change in the form of the conductor or the formation of the rail aperture.

On the drawings:

Fig. l is an enlarged side view of a bonding pin constructed in accordance with my invention;

Fig. 2, a view looking of the bonding pin;

Fig. 3, a view partly in section showing the manner of connecting rails with my bonding pin;

Fig. 4 an enlarged view taken on the line 55 of Fig. 3, showing the bonding pin in at the smaller end Serial No. 617,969.

place before it is driven into the rail aperture;

Fig. 5, a similar view showing the bonding pin driven into place; and

Fig. 6 an enlarged view showing the rail insection on the line 66 of Fig. 3.

Referring to the drawings, the numerals 1-1 indicate two adjoining rails, 2 a conductor for connecting the two rails and 33 apertures in the rails in which the ends of the conductor 2 are secured. The bonding pin is indicated as a whole at 4 and is tapereol at one end as indicated at 5 to facilitate insertion in the aperture 3 of the rail. A groove (3 extends from end to end of the pin to receive the conductor 2, and the portion 7 of the pin beyond the tapered portion 5 is also tapered, but more gradual than the portion 5, so as to afford a driving lit in the aperture 3, whereby the pin is not only secured in the aperture but also caused to grip the conductor 2 in the groove 6.

The taper of the portion 5 of the pin may be of ordinary conical formation, that is, of such a form that it is circular in cross section, but the portion 7 is of a special tapered form to effect amore substantial clampmg or gripping of the conductor 2 in the groove 6 and also to avoid unnecessary muti lation of the wire. To this end the portion 7 is not tapered in the mid plane AA of the groove 6, but is of a uniform thickness substantially the same or a trifle greater than the diameter of the rail aperture 3 in which it is to be inserted. In other words, assuming that the groove 6 is omitted as indicated by dotted lines in'Fig. 2, the tangent planes B-B, CG at opposite sides of the pin are substantially parallel. The pin is however, tapered in the plane D-D at right angles to the mid plane-being formed about divergent axes so that the portion 7 is of gradually increasing elliptical or oval transverse form from the inner end of the taper 5 to the remote end of the pin.

With this construction there is practically no wedge action on the pin in the mid-plane A-A of the groove, but merely a snug lit, and the groove 6 is arranged with the bot-- tom thereof parallel with the planes BB, C-C so that the conductor 2 fits in the groove with the axes thereof substantially parallel with the planes B-B, C--C. thereby substantially obviating wedge action between the conductor and the wall of the aperture 3. The groove 6 is also of such a depth llltl that the conductor 52 is seated well in the groove so that only a ,"nnall portion ot the conductor is exposul tor o cement with the rail aperture, such en enient being provided to all'ord a scrapnng action hetven the conductor and edge of the rail aperture to clean. the surilaces and insure a good electrical connection between the corn doctor and rail.

ll ith the construction described, when the conductor 2 is laid in the groove (3 and the pin driven into the rail aperture 3, the coinprcssing strain oi the wedge engagement is app ied to the pin at op .)osite sides of? the roove (i and only a snug lit occurs between ie pin aid conductor and rail aperture in .plane fir-fr oi the groove. thereby mid i l'ording relief for the compressing strain. circnniilierential directions at each side oi he we lge plane D l). This results in a 3h crowding ot the grooved side of the run against the correspoiuling side of the aperture 3, su'liicient to press the coinlnetor firmly against the rail aperture, and also causes the lips or outer c.-;treinities ot the side walls of the groove to fold over and con'ipress the top and bottom of the conductor substantially as shown in Fig. 5, so that the conductor is clamped down in the groove 6 and snugly engaged bv the pin l: entirely therearound excepting at the portion of its surface where contact is had between the conductor and A perfect electrical connection is thus atiorded as well as a substantial mechanical connection without the excessive mutilation or peeling back and shearing Of the conductor as in previous bonding pin structures and the capacity of the conductor is practically unimpaired and liability oi? breakage or shearing reduced to a minimum.

Yfhile I have shown and described my invention in a preferred torin I am aware that various changes and modifications may be made without departing from the principles of my invention. the scope of which is to be determined by the appended claims.

I claim as my invention:

1. An electrical connector comprising a longitudinally grooved body having a tapered end portion. the remaining portion of the body having the same thickness throughout on a plane bisecting the groove and of gradually increasing thickness on planes at right angles to the plane bisecting the groove.

2. An electrical connector consisting of a longitudinally grooved pin of uniform thickness tor a major portion of its length from its head end on a plane bisecting the groove, and of gradually increasing thickness on planes at right angles to the plane l'iisecting the groove.

3. An electrical connector consisting of a longitudinally grooved pin of substantially trance end and a longitudinal groove of elliptical cr section having an entering portion, the thickness of the pin on a plane bit-setting the groove being constant beyond the enter-hug portion, and the thickness of the pin on planes at right angles to the plane inserting the groove gradually in creasii'ig to the end ol' the pin remote from the entering portion.

4 The con'ibination with a rail having an .apernu'e therein, of a longitudinally grooved pin adapted to be inserted in said aperture, said pin being of gradually increasing thickness on planes at right angles to the plane hisccting the groove so that the maximum compressing strain imposed thereon when inserted .in the aperture is at right angles to said plane bisecting the groove.

5. 'lhe combination with a rail having a :ircular aperture of a tapered longitudinal- 'ooved pin adapted to be inserted in aperture, said pin being or a form so the maximum compressing strain iniposed thereon when inserted in the aperture of the rail is at right angles to a plane hicecting the goove.

6. it bonding pin having a tapered por tion and a longitudinal groove with the bottom thereoi parallel to the axis of the pin, said oin being of uniform thicki'zcss on a plane bisecting the groove beyond the tapered portion and of gradually increaing thickness on one side of the plane bisccting the groove.

2'. in electrical connector consistingoi a longitudinally grooved pin having an entrance end and being of uniform thichn as on a plane bisecting the groove and extend ing to the longitudinal axis of the pin, 'iroin the entrance end to the head end and of grad ually increasing thickness on opposite sides of the plane bisecting the groove.

8. A bonding pin having a tapered enuntorm depth with the bottom thereof pain. to the axis otthe pin, the pin being oi uniform diameter in a radial plane bisecti re. the groove and incl asing in diamctuon one side ot the bisccting plane from the tapered entrance end to the remote end oi the pin to provide a pin of substantiall oval cross-section with portions increasi in radial dimension and eccentricity toward the head end or the pin on one or more sides 01 the groove.

9. An electrical connector comprising a lon itudinally grooved pin adapted to he inserted in a circular aperture of a rail web or the like. the groove of which is aeapted to receive a conductor wire, said pin l of such form that the maximum compress. strain imposec thereon agains the wire when the pin is driven into the aperture with the wire in the groove. is at ri ht angle-'5 to the adial plane l'zisecting the groove.

LOUIS H. 

